A thermodynamic comparison of external and internal exhaust gas dilution for high-efficiency internal combustion engines

Caton, Jerald A.

doi:10.1177/1468087414560593

Cited by 11 publications

(5 citation statements)

References 38 publications

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“…A wide variety of valve strategies have been used to accomplish the internal exhaust gas dilution [29]. These strategies include negative valve overlap (NVO), delayed exhaust valve closing (dEVC), and the use of a second exhaust event during the intake process.…”

Section: Internal Exhaust Gas Dilutionmentioning

confidence: 99%

The Thermodynamics of Internal Combustion Engines: Examples of Insights

Caton

2018

Inventions

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A major goal of the development of internal combustion (IC) engines continues to be higher performance and efficiencies. A major aspect of achieving higher performance and efficiencies is based on fundamental thermodynamics. Both the first and second laws of thermodynamics provide strategies for and limits to the thermal efficiencies of engines. The current work provides three examples of the insights that thermodynamics provides to the performance and efficiencies of an IC engine. The first example evaluates low heat rejection engine concepts, and, based on thermodynamics, demonstrates the difficulty of this concept for increasing efficiencies. The second example compares and contrasts the thermodynamics associated with external and internal exhaust gas dilution. Finally, the third example starts with a discussion of the Otto cycle analysis and explains why this is an incorrect model for the IC engine. An important thermodynamic property that is responsible for many of the observed effects is specific heat.

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Section: Internal Exhaust Gas Dilutionmentioning

confidence: 99%

The Thermodynamics of Internal Combustion Engines: Examples of Insights

Caton

2018

Inventions

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“…The effects of the EGR rate on the gas emissions of the DME-methanol engine operated in the P-PCCI combustion mode are similar to those in the DICI mode, as shown in Figures 16 to 19. In the P-PCCI combustion mode, the increase in the EGR rate can significantly reduce NOx emissions, as shown in Figure 16.…”

Section: Emissions P-pcci Modementioning

confidence: 60%

“…EGR is thought to be a midtier NOx reduction strategy. 19,20 By adopting EGR, the NOx emissions of DME engines could meet Euro IV and V. 21 Another strategy to suppress the generation of NOx emissions is the clean combustion mode, that is, HCCI combustion, PCCI combustion, and P-PCCI combustion. Kim 22 investigated the strategy of NOx reduction for DME engines, and PCCI and P-PCCI combustions were adopted in the experiments.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of effects of exhaust gas recirculation and combustion mode on combustion, emission, and performance of DME‐methanol ‐fueled turbocharged c ommon‐rail engine

Sun

Liu

Qiao

et al. 2021

Intl J of Energy Research

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In this study, the effects of exhaust gas recirculation (EGR) on the combustion, performance, and emission of a six-cylinder turbocharged common-rail dimethyl ether (DME) engine with methanol blends are experimentally investigated, and the proportions of methanol considered are 0% (DME), 5% (M5), 10% (M10), and 15% (M15) by weight. A comparison of direct-injection compression ignition (DICI) combustion and partially premixed charge compression ignition (P-PCCI) combustion is conducted, and P-PCCI combustion is achieved by a two-stage injection. The results indicate that the NOx emissions decrease, but the CO and HC emissions increase approximately linearly as the EGR rate increases. The addition of methanol delays the combustion, shortens the combustion duration, and increases the pressure rise rate. In addition, the NOx emissions decrease, whereas the CO and HC emissions increase significantly as the methanol proportion increases. M5 exhibits the lowest fuel consumption for both the P-PCCI and DICI combustions. Compared to the DICI mode, in the P-PCCI mode, the peak in-cylinder pressure is higher, maximum pressure rise rate is considerably lower, NOx emissions are better suppressed and approximately 20% lower, CO and HC emissions are greater, and particle emission is slightly lower.

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“…One reason is the decrease of the combustion efficiency with large PVO durations as presented in Figure 11. In addition, the indicated efficiency is reduced further due the increase in heat transfer resulted of the residual gas dilution as reported by [29].…”

Section: Cov Of Imep [%]mentioning

confidence: 83%

Efeitos da Variação dos Eventos de Válvulas na Combustão, Desempenho e Emissões de um Motor de Ignição por Centelha operando em Carga Parcial com Etanol

Golke¹,

Rohrig²,

Prante³

et al. 2021

Blucher Engineering Proceedings

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The stricter legislation on pollutant emissions and the demand for less CO2 per km has been driven the industry on a pursuit trade off in internal combustion engines (ICE). Urban area frequently stands for engine part load operation. For this reason, high engine performance on this map region is essential to mitigate greenhouse gas emission and improve urban air quality. However, spark ignition engine efficiency is worsened by load control method in part load that increase the pumping loses. Therefore, the present work investigated the effects on combustion, performance and emissions by varying the intake and exhaust valve timings. The tests were carried out in a three-cylinder 1.0 l engine with direct injection system. The engine was fueled with hydrous ethanol and the tests were performed at 4 and 8 bar IMEP, 1500 rpm and stoichiometric lambda. The valve timing setting was from a locked position of 5 CAD of NVO to 85 CAD of PVO. The spark timing was adjusted to maintain the CA50 at 10 CAD aTDCf. The injection timing and pressure were kept at 30 CAD aTDCi and 100 bar. The COVIMEP was limited at 3%. The results showed slightly increase in engine efficiency and decrease of NOX emission with higher positive valve overlap.

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A thermodynamic comparison of external and internal exhaust gas dilution for high-efficiency internal combustion engines

Cited by 11 publications

References 38 publications

The Thermodynamics of Internal Combustion Engines: Examples of Insights

The Thermodynamics of Internal Combustion Engines: Examples of Insights

Experimental study of effects of exhaust gas recirculation and combustion mode on combustion, emission, and performance of DME‐methanol ‐fueled turbocharged c ommon‐rail engine

Efeitos da Variação dos Eventos de Válvulas na Combustão, Desempenho e Emissões de um Motor de Ignição por Centelha operando em Carga Parcial com Etanol

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